As winter’s grip loosens, it’s time for pool service professionals to start planning for the pool opening season. For many, reopening pools that have been dormant through the winter months is a significant undertaking.
Each year, as pools are awakened from their winter slumber, service companies kick off their annual preparations by recruiting and training new staff for the busy season ahead.
The demand for spring pool openings creates a bustling time for the industry, particularly in regions that experience severe winter weather. The 2023 Service Industry News Survey revealed that the average charge for spring pool openings was around $500, underscoring the lucrative nature of this seasonal work.
Reopening a pool for the warmer months is often a comprehensive task. In areas that experience harsh winters, this includes removing pool covers, setting up equipment, repairing any weather-related damage, evaluating the condition of the pool shell and deck, and restoring water chemistry to safe levels.
In warmer climates, spring preparations might simply involve adjusting sanitizer levels and rebalancing the water.
With the swimming season rapidly approaching, now is the optimal time for service companies to enhance their operations and excite their clients about getting their pools season-ready.
Spring pool openings not only represent a significant business opportunity — whether the pool has been completely closed or just minimally used — but they also provide a chance to train seasonal employees on essential aspects of pool maintenance, including water chemistry and equipment servicing.
Opening pools provides a comprehensive annual inspection opportunity, offering new technicians a valuable learning experience. It’s beneficial for newcomers to shadow experienced professionals, gaining insights into everything from equipment maintenance to achieving perfect water balance and sanitation.
Ensuring swimmer safety through proper water chemistry is paramount in preparing a pool for the season. The most critical chemical aspect to monitor is the sanitizer level, essential for maintaining hygienic swimming conditions by controlling bacteria and algae growth.
A detailed discussion on sanitizers will be featured in the May 15 issue of Service Industry News. The focus here shifts to another vital responsibility of pool and spa professionals: Achieving and maintaining balanced water. This not only protects pool surfaces and equipment but also ensures the water is invitingly clear and appealing to users.
Water balance involves managing physical parameters that influence each other, aiming for water that is neither prone to scaling nor corrosive. This balance is assessed using the Langelier Saturation Index, which evaluates the saturation level of dissolved solids in the water at various temperatures, considering additional factors such as pH, total alkalinity, calcium hardness, and total dissolved solids.
Maintaining balanced water in pools is not merely a matter of aesthetics; it is a fundamental aspect of pool care that ensures the longevity of equipment and the preservation of pool surfaces. This delicate equilibrium involves monitoring and adjusting various water parameters to prevent corrosion or scale formation. Let’s delve deeper into the critical parameters of pH, total alkalinity, calcium hardness, water temperature, and total dissolved solids (TDS).
pH
The pH scale serves as a measure of how acidic or basic the water is. Ranging from 0 to 14, a pH of 7 is considered neutral. Values below 7 indicate acidity, while those above 7 suggest alkalinity. Maintaining a balanced pH is crucial because deviations can lead to adverse effects on pool components.
Acidic water with a low pH is corrosive to metal fixtures, posing a threat to the structural integrity of the pool. Conversely, high pH, when combined with elevated total alkalinity or calcium hardness, can lead to the precipitation of calcium carbonate, resulting in scale formation on pool surfaces. The ideal pH range for pool water is typically between 7.2 and 7.8.
When the pH is too low, sodium carbonate (soda ash, chemical formula Na2CO3) is recommended for adjustment. Conversely, when the pH is too high, muriatic acid (HCl) is commonly used. The careful application of these chemicals helps maintain a balanced pH and mitigates potential damage to the pool structure.
Total Alkalinity
Total alkalinity is a measure of the water’s buffering capacity against pH changes. Adequate total alkalinity, within the range of 80 to 120 ppm, is essential for preventing rapid pH fluctuations. The buffering capacity is maintained through a complex equilibrium reaction involving carbon dioxide, carbonic acid, bicarbonate ions, and carbonate ions.
Insufficient total alkalinity results in water with minimal buffering capacity, leading to erratic pH changes. On the other hand, excessive total alkalinity can contribute to rising pH levels and the formation of scale. Adjusting total alkalinity to the proper level is a prerequisite before addressing pH concerns.
Sodium bicarbonate (chemical formula NaHCO3) is commonly employed to raise low total alkalinity, acting as a weak base that adds bicarbonate ions to the water. For lowering high total alkalinity, acids such as muriatic acid or sodium bisulfate are used, converting bicarbonates to carbonic acid.
Cyanuric Acid Affects Total Alkalinity
It’s essential to note that cyanuric acid affects the total alkalinity test. Cyanuric acid is generally present in outdoor pools using a chlorinebased sanitizer and is one of the chemical components of trichlor or sodium dichlor. When measuring total alkalinity, cyanuric acid affects the test by giving a higher test result than the true carbonate alkalinity.
But when measuring total alkalinity, only the carbonate component of the total alkalinity test is relevant and must be isolated from the measured test result.
To make the correction, measure both the total alkalinity and the cyanuric acid concentrations. Then subtract the cyanuric acid multiplied by a correction factor from the total alkalinity measured. The correction factor is pH dependent, but at normal pool pH levels, it is about 0.33. For example, if the total alkalinity is measured to be 100 ppm, and the cyanuric acid is measured to be 50 ppm, then the carbonate alkalinity should be approximately 84:
TA – (CYA x 0.33) = Carbonate TA 100 – (50 x 0.33) = 83.5 Calcium Hardness
Calcium hardness measures the concentration of calcium in the water. While it might seem counterintuitive, having some calcium in the water is important to maintain equilibrium. Without added calcium, the water becomes aggressive, leaching minerals from pool surfaces and metal fixtures in a corrosive manner.
However, high calcium concentrations, especially when combined with elevated total alkalinity, can lead to the formation of solid precipitate particulates, causing cloudiness or adhering to pool surfaces as scale. The recommended calcium hardness levels typically range from 150 to 1,000 ppm, with an ideal range of 150 to 250 ppm.
Testing the calcium hardness of the source water is important when filling a new pool or replenishing water in a drained pool. If the calcium hardness is too low, calcium chloride (CaCl2) can be added to achieve the desired balance. Conversely, if the calcium hardness is excessively high, more advanced methods such as water softeners or reverse osmosis may be considered to remove calcium ions.
If the source water calcium hardness is only a little high, the water balance can be controlled by maintaining the proper total alkalinity and pH.
Water Temperature
Water temperature is a variable that can significantly impact water chemistry. While controlling water temperature is often beyond human control, understanding its influence is crucial for assessing other water parameters. Calcium becomes less soluble at higher temperatures, increasing the likelihood of scale formation.
In most cases, managing water temperature is subject to natural factors. Nevertheless, recognizing the role of temperature in water chemistry aids in anticipating potential changes in other parameters. Colder water tends to be more aggressive, while warmer water is more prone to scale formation.
Knowing this fact allows pool pros to adjust the other water balance parameters accordingly.
Total Dissolved Solids (TDS)
Total dissolved solids (TDS) is a measure of the concentration of dissolved solids in water, typically expressed in parts per million (ppm). The electrical conductivity of water, measured with a conductivity meter, provides an indication of TDS.
In pools using a salt chlorine generator, TDS levels of up to 4,000 ppm are considered normal. For traditionally chlorinated pools, maintaining TDS between 1,000 and 2,000 ppm is generally acceptable. Elevated TDS can indicate impurities in the water, potentially affecting the effectiveness of algaecides, increasing scale formation, and contributing to surface staining.
If the TDS is more than 1,500 ppm from the startup TDS, it could be evidence of poor water conditions, and a partial draining may be in order.
The TDS at the startup includes the TDS from the source water as well as any salt and startup chemicals that were added.
For this reason, it’s a good idea to test the source water at the time of filling and prior to refilling a partially drained pool.
TDS is a comprehensive measure, encompassing minerals from source water, chemicals added to the water (including balancing chemicals, cyanuric acid, and disinfectants), and contaminants such as fertilizer, insects, leaves, dirt, pollen, body oils, and other bather waste. It’s important to note that while TDS is an essential parameter, it is the least critical factor in water balance.
Routine testing, especially during pool filling or refilling, aids in assessing TDS. However, unilaterally draining a pool due to high TDS alone parameters. Total alkalinity, pH, calcium hardness, water temperature, and total dissolved solids collectively contribute to the overall health and sustainability of the pool environment.
Regular testing, judicious use of chemicals, and environmentally conscious practices are key elements in preserving water quality and ensuring a safe and enjoyable swimming experience.
